JPH072883B2 - Vulcanized rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION a. Field of Industrial Application The present invention has excellent gasoline resistance, gasohol resistance, sour gasoline resistance, sour gasohol resistance, and excellent ozone resistance and heat resistance. It relates to a vulcanized rubber composition.

b. Conventional technology In recent years, the atmosphere in which gasoline-resistant rubber is used has tended to become even hotter as a result of improvements in engines, etc. for the purpose of exhaust emission control measures and performance improvements in automobiles. A gasoline (oil) resistant rubber having excellent ozone resistance is required. In addition, gasoline is oxidized and sour gasoline (It means gasoline containing peroxide generated by the oxidation of gasoline. For details, see A. Nersasian:
(Described in Rubber and Plastics News June 26 (1978)), which causes a problem of degrading rubber.

Further, due to the worldwide tight supply and demand of crude oil, it has been attempted to mix alcohol with gasoline.
This alcohol-blended gasoline (gasohol) also has a problem that it is oxidized like normal gasoline to generate sour gasohol, which deteriorates rubber.

Conventionally, butadiene-acrylonitrile rubber has been widely used as a gasoline resistant rubber for applications such as hoses, gaskets, O-rings, packings and oil seals.

c. Problems to be Solved by the Invention However, the butadiene-acrylonitrile rubber is
Since the heat resistance is poor and the sour gasoline resistance is insufficient, it is difficult to obtain a rubber component having sufficient reliability in the environment where it comes into contact with gasoline at a high temperature as described above.

As a method for improving this, it is known to improve the sour gasoline resistance and ozone resistance by using a blend of butadiene-acrylonitrile rubber and polyvinyl chloride, but it is known (JP-A-55 No. 89838), this does not improve heat resistance, and gasohol resistance is not sufficient.

Conventionally, acrylic rubber has been used as a material having excellent oil resistance, heat resistance, and ozone resistance, but such rubber is inferior in gasoline resistance, gasohol resistance, and sour gasoline resistance, and has recently been required for automobiles. It is unsuitable because it cannot satisfy the performance required for the engine peripheral equipment of, and this improvement is required.

For example, as such an improving means, a rubber composition comprising a mixture of an acrylic rubber and a vinylidene fluoride rubber has been proposed, but such a composition still has sufficient gasoline resistance, gasohol resistance and sour gasoline resistance. Has not reached a certain level.

d. Means for Solving Problems The present inventors have sought to obtain a rubber material having excellent gasoline resistance, gasohol resistance, sour gasoline resistance, sour gasohol resistance, ozone resistance, and heat resistance. As a result of intensive studies, an acrylic rubber having a certain polymerization composition,
A vulcanized rubber composition comprising a mixture of an acrylic rubber, a fluororubber, at least one rubber selected from other rubber groups excluding butadiene-acrylonitrile and its hydride and a vinylidene fluoride resin has ozone resistance,
Not only is it excellent in heat resistance, gasoline resistance, and sour gasoline resistance, it also has new required performances such as gasohol resistance and sour gasohol resistance, and also has good tensile strength, elongation and gasoline resistance and cold resistance. The inventors have found that they have a balance and arrived at the present invention.

That is, the present invention relates to (A) 30% to 99.9% by weight of an alkyl acrylate and / or an alkoxy substituted alkyl acrylate compound, and (B) a crosslinkable monomer of 0.1.
To 10% by weight, and (C) 0 to 70% by weight of another ethylenically unsaturated compound copolymerizable with the above (A) and (B), an acrylic rubber (I) and an acrylic rubber. , Fluororubber, butadiene-acrylonitrile rubber, and at least one rubber (II) selected from the group of other rubbers except its hydride, and (I)
A mixture (α) containing a mixture (α) having a weight ratio of / (II) of 99.9 / 0.1 to 70/30 and a vinylidene fluoride resin (III) containing 90 mol% or more of vinylidene fluoride.
/ Vinylidene fluoride (III) weight ratio is 95 / 5-40 / 60
The present invention provides a vulcanized rubber composition characterized by:

The acrylic rubber (I) used in the present invention includes: (A) an acrylic acid alkyl ester and / or an acrylic acid alkoxy-substituted alkyl ester compound, (B) a crosslinkable monomer, and (C) the above (A) and (B). A multi-component copolymer rubber composed of other components, which are copolymerizable with other ethylenically unsaturated compounds, is used.

The acrylic acid alkyl ester as the component (A) has the following general formula (i) [In the formula, R ₁ represents an alkyl group having 1 to 18 carbon atoms. ], Such as methyl acrylate,
Ethyl acrylate, n-propyl acrylate, n-
Butyl acrylate, isobutyl acrylate, n-pentyl acrylate, isoamyl acrylate, n-hexyl acrylate, 2-methylpentyl acrylate, n-octyl acrylate, 2-ethylhexyl acrylate, n-decyl acrylate, n-dodecyl acrylate, n-actadecyl acrylate And the like. Methyl acrylate, ethyl acrylate, n-propyl acrylate and n-butyl acrylate are preferable, and methyl acrylate and ethyl acrylate are particularly preferable.

The (A) component acrylic acid alkoxy-substituted alkyl ester has the following general formula (ii) And is represented by, for example, 2-methoxyethyl acrylate, 2-ethoxyethyl acrylate, 2-
(N-propoxy) ethyl acrylate, 2- (n-butoxy) ethyl acrylate, 3-methoxypropyl acrylate, 3-ethoxypropyl acrylate, 2-
(N-propoxy) propyl acrylate, 2- (n-
Butoxy) propyl acrylate and the like can be mentioned, and 2-methoxyethyl acrylate and 2-ethoxyethyl acrylate are preferable, and 2-methoxyethyl acrylate is particularly preferable.

The crosslinkable monomer which is the component (B) is a monomer capable of introducing a crosslinked structure into the copolymer obtained by copolymerization, and examples thereof include a diene compound and dihydrodicyclopentadienyl. At least one compound selected from the group consisting of a group-containing (meth) acrylic acid ester, an epoxy group-containing ethylenically unsaturated compound, an active halogen-containing ethylenically unsaturated compound and a carboxyl group-containing ethylenically unsaturated compound may be mentioned. it can.

Among the crosslinkable monomers of the component (B), examples of the diene compound include non-conjugated dienes such as alkylidene norbornene, alkenyl norbornene, dicyclopentadiene, methylcyclopentadiene and dimers thereof, and conjugated dienes such as butadiene and isoprene. It is desirable to use a non-conjugated diene selected from the group consisting of alkylidene norbornene, alkenyl norbornene, dicyclopentadiene, methylcyclopentadiene and dimers thereof.

In addition, among the crosslinkable monomers of the component (B), examples of the dihydrodicyclopentadienyl group-containing (meth) acrylic acid ester include dihydrodicyclopentadienyl (meth) acrylate and dihydrodicyclopentadienyloxyethyl. (Meth) acrylate is preferred.

Further, among the compounds of the component (B), the epoxy group-containing ethylenically unsaturated compound is preferably allyl glycidyl ether, glycidyl methacrylate, or glycidyl acrylate.

Furthermore, among the compounds of the component (B), active halogen-containing ethylenically unsaturated compounds and specific examples are vinylbenzyl chloride, vinylbenzyl bromide, 2-
Chlorethyl vinyl ether, vinyl chloroacetate, vinyl chloropropionate, allyl chloroacetate, allyl chloropropionate, 2-chloroethyl acrylate, 2-chloroethyl methacrylate, chloromethyl vinyl ketone, 2-chloroacetoxymethyl-
5-norbornene and the like can be mentioned, and among these, vinyl chloroacetate, 2-chloroethyl vinyl ether, vinylbenzyl chloride, 2-chloroethyl methacrylate and 2-chloroethyl acrylate are preferable.

Further, among the compounds of the component (B), specific examples of the carboxyl group-containing ethylenically unsaturated compound include:
Examples thereof include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, maleic acid, fumaric acid and itaconic acid.

As the other ethylenically unsaturated compound of the component (C), various compounds can be used if necessary, and examples thereof include acrylic acid, methacrylic acid, crotonic acid, 2-pentenoic acid, and maleic acid. Carboxyl group-containing compounds such as acids, fumaric acid, itaconic acid, 2-cyanoethyl acrylate, 3-cyanopropyl acrylate,
Cyano-substituted alkyl (meth) acrylates such as 4-cyanobutyl acrylate, methacrylates such as methyl methacrylate and octyl methacrylate, alkyl vinyl ketones such as methyl vinyl ketone, vinyl and allyl ethers such as vinyl ethyl ether and allyl methyl ether, styrene, α-methylstyrene, chlorostyrene, vinyl aromatic compounds such as vinyltoluene,
Vinyl nitriles such as acrylonitrile and methacrylonitrile, acrylamide, methacrylamide, N-
Vinylamides such as methylolacrylamide, 1,1-
Dihydroperfluoroethyl (meth) acrylate, 1,
1-dihydroperfluoropropyl (meth) acrylate, 1,1,5-trihydroperfluorohexyl (meth)
Acrylate, 1,1,2,2-tetrahydroperfluoropropyl (meth) acrylate, 1,1,7-trihydroperfluoroheptyl (meth) acrylate, 1,1-dihydroperfluorooctyl (meth) acrylate, 1,1-
Fluorine-containing acrylic acid ester such as dihydroperfluorodecyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dibutylaminoethyl (meth)
Tertiary amino group-containing monomers such as acrylates, hydroxyl group-containing compounds such as 1-hydroxypropyl (meth) acrylate, 2-hydroxypropyl (meth) acrylate and hydroxyethyl (meth) acrylate, and ethylene, propylene, vinyl chloride, chloride Examples thereof include vinylidene, vinyl fluoride, vinylidene fluoride, vinyl acetate and alkyl fumarate.

Of these, 2-cyanoethyl acrylate, acrylonitrile, ethylene and vinyl acetate are preferable, and 2-cyanoethyl acrylate and acrylonitrile are particularly preferable.

In addition, a preferable combination of the component (A) and the component (C) is an acrylic acid alkyl ester of the component (A) and /
Alternatively, the acrylic acid alkoxy-substituted alkyl ester compound is at least one compound selected from the group of methyl acrylate, ethyl acrylate and methoxyethyl acrylate, and the other ethylenically unsaturated compound of the component (C) is acrylonitrile.

(A) and (B) in the acrylic rubber (I) of the present invention
And the composition ratio of the component (C) is 30 to 99.9% by weight of the component (A), 0.1 to 10% by weight of the component (B) and 0 to 7 of the component (C).
It is 0% by weight.

When the content of the component (A) is less than 30% by weight, the normal physical properties of the acrylic rubber such as tensile strength and elongation are poor, which is not preferable. It is preferably 50% by weight or more, particularly preferably 70%.
It is more than weight%.

If the amount of the component (B) is less than about 0.1% by weight, it takes a long time to crosslink the acrylic rubber. On the other hand, if it exceeds 10% by weight, the rubber becomes hard and the elongation of the crosslinked rubber decreases, which is not preferable. It is preferably 1 to 7% by weight, more preferably 2 to 5% by weight.

Further, if the amount of the component (C) exceeds about 70% by weight, the amount of the component (A) becomes too small, which is not preferable.

The acrylic rubber (I) can be produced by emulsion polymerization using a usual radical polymerization catalyst.

At least one rubber (II) selected from the group of other rubbers other than the acrylic rubbers, fluororubbers, butadiene-acrylonitrile rubbers and hydrides thereof used in the present invention is chloroprene rubber, hydrin rubber, chlorosulfonated. Examples thereof include polyethylene, chlorinated polyethylene, silicone rubber, ethylene-propylene- (diene) rubber, styrene-butadiene rubber, polybutadiene rubber, butyl rubber, isoprene rubber, and natural rubber. Among them, when hydrin rubber or silicone rubber is used, , Has an effect of improving cold resistance, and hydrin rubber is particularly preferable.

Next, the vinylidene fluoride resin (II
I) is polyvinylidene fluoride and vinylidene fluoride and hexafluoropropene, pentafluoropropene,
Trifluoroethylene, trifluorochloroethylene,
One or more copolymers of tetrafluoroethylene, vinyl fluoride, perfluoro (methyl vinyl ether), perfluoro (propyl vinyl ether), vinyl acetate, ethylene, propylene, butadiene, styrene, acrylic acid ester, etc. And the content of vinylidene fluoride is 90% or more, preferably 95 mol%
That is all. A vinylidene fluoride copolymer having a vinylidene fluoride content of less than 90 mol% is not preferable in terms of gasoline resistance, gasohol resistance, sour gasoline resistance and sour gasohol resistance. The vinylidene fluoride resin is
Although not particularly limited, those having a polymerization degree of 100 to 100,000 are preferably used.

As described above, the vulcanized rubber composition of the present invention comprises the acrylic rubber (I), an acrylic rubber, a fluororubber and a butadiene-
At least one rubber (II) selected from the group of other rubbers other than acrylonitrile rubber and its hydride, and the weight ratio of them (I) / (II) is 99.9 / 0.1-
70/30 mixture (α) and vinylidene fluoride 90
The vinylidene fluoride resin (III) is contained in an amount of not less than mol%, but the ratio of the two used is the mixture (α).
The weight ratio of vinylidene fluoride resin is 95/5 to 40/60.

That is, the amount of the rubber (II) used is at most less than 30 parts by weight in 100 parts by weight of the mixture (α), and when it is 30 parts by weight or more, sour gasoline resistance and the like deteriorate. It is preferably 20 parts by weight or less.

The amount of vinylidene fluoride resin (III) used is at least 5 parts by weight in 100 parts by weight of the mixture of mixture (α) and vinylidene fluoride resin (III). If less than about 5 parts by weight, the effect of improving gasohol resistance is improved. Is not observed, and it is preferably 10 parts by weight or more. Vinylidene fluoride resin (II
As the amount of I) increases, the workability deteriorates and the cost increases, so the upper limit of the amount used is naturally determined and is usually 60 parts by weight or less, preferably 50 parts by weight or less.

The use ratio of the mixture (α) and the vinylidene fluoride resin (III) in the composition of the present invention can be appropriately determined within the above range depending on the purpose of use and required performance.

The method of mixing the composition of the present invention is not particularly limited, but the following method can be used, for example.

(A) At least one selected from the group consisting of acrylic rubber and other rubbers other than acrylic rubber, fluororubber, butadiene-acrylonitrile rubber and hydrides thereof.
After mixing the seed rubber with a mixer such as a roll, Banbury mixer, or intermixer, then add vinylidene fluoride resin and mix with a mixer such as a roll, Banbury mixer, or intermixer. Method.

(B) An acrylic rubber, at least one rubber selected from the group consisting of acrylic rubber, fluororubber, other rubbers other than butadiene-acrylonitrile and its hydride, and vinylidene fluoride resin are rolled at a time, A method of mixing using a mixer such as a Banbury mixer or an intermixer.

(C) At least one selected from the group consisting of acrylic rubber and other rubbers other than acrylic rubber, fluororubber, butadiene-acrylonitrile rubber and hydrides thereof.
Seed rubber and vinylidene fluoride resin are mixed in a latex or suspension state, respectively, and then coagulated by coagulation treatment, or (d) above (a) and (c) are used in combination Or a method of using the above (b) and (c) together.

The vulcanized rubber composition of the present invention is blended with usual compounding agents such as a reinforcing agent, a filler, a plasticizer, a release agent, a softening agent, a stabilizer, etc. After blending with (α), it can be mixed with a vinylidene fluoride resin by any one of the methods (a), (b), (c) and (d), and the mixture (α) and vinylidene fluoride can be mixed. It is also possible to mix the resin (III) and then mix.

When the mixture (α) and the vinylidene fluoride resin (III) are mixed using a roll, a Banbury mixer, an intermixer or the like, specifically, 150 to 250 ° C., preferably 150
Perform at ~ 200 ° C. If the mixing temperature exceeds 250 ° C, the rubber is deteriorated, which is not preferable. If the mixing temperature is less than 150 ° C, the blended state is insufficient and the physical properties are deteriorated.

The vulcanized rubber composition of the present invention can be easily obtained as a crosslinked product by a usual crosslinking method.

As the cross-linking agent used in the cross-linking method, a suitable compound can be selected depending on the kind of the functional group introduced into the acrylic rubber and used for cross-linking.

For example, by copolymerizing a diene compound or a dihydrodicyclopentadienyl group-containing (meth) acrylic acid ester,
When a carbon-carbon double bond is introduced, cross-linking used for sulfur, thiuram-based and other so-called vulcanizing agents, and general diene-based rubbers such as organic peroxides (styrene-butadiene rubber, isoprene rubber, etc.) The agent can be preferably used.

When an epoxy group-containing ethylenically unsaturated compound is copolymerized to introduce an epoxy group into an acrylic rubber, polyamine carbamates, ammonium organic carboxylates, dithiocarbamate salts, and alkali metal organic carboxylates are used. A combination of sulfur compounds can be used as a crosslinking agent.

Furthermore, when an active halogen-containing ethylenically unsaturated compound is copolymerized with an acrylic rubber to introduce an active halogen group, a polyamine carbamate, an organic ammonium carboxylate, an organic carboxylic acid alkali metal salt and a sulfur compound are combined. It is possible to preferably use the ones that are used.

Acrylic rubber, fluororubber used in the present invention,
In at least one rubber selected from the group of other rubbers other than conjugated diene-α, β unsaturated nitrile copolymer rubber and its hydride, a crosslinking agent used for ordinary crosslinking is also preferably added. , Can be used.

From the viewpoint of improving cold resistance, it is preferable to add a plasticizer, but as the plasticizer, a phthalic acid derivative compound such as diethyl phthalate, di- (2-ethylhexyl) phthalate, dibutyl phthalate, di-n-octyl phthalate or dimethyl cyclohexyl phthalate, Isophthalic acid derivative compounds such as diisooctyl isophthalate, tetrahydrophthalic acid derivative compounds such as di- (2-ethylhexyl) tetrahydrophthalate, di- (2-ethylhexyl) adipate, di- (butoxyethoxyethyl) adipate, butyl Adipic acid derivative compounds such as diglycol adipate, azelaic acid derivative compounds such as di- (2-ethylhexyl) azelate, sebacic acid derivatives such as di- (2-ethylhexyl) sebacate, di-n-butyl sebacate Compound, fatty acid derivative compound such as diethylene glycol monolaurate, tributoxyethyl phosphate, tri- (2-ethylhexyl) phosphate, phosphoric acid derivative compound such as triphenyl phosphate, glycol derivative such as dibutylmethylenebisthioglycolate Other compounds such as compounds, glycerin derivative compounds and epoxy derivative compounds are exemplified by polyester type compounds, polyether type compounds, polyether / ester type compounds and the like as polymerization type plasticizers.

Among these, adipic acid derivative compounds, phosphoric acid derivative compounds, polyester compounds of polymerization plasticizers, polyether compounds, polyether ester compounds are preferable, and di- (butoxy ethoxy ethyl) adipate,
Tributoxyethyl phosphate and polyether / ester compounds are preferred.

The vulcanized rubber composition of the present invention is excellent in gasoline resistance, sour gasoline resistance, ozone resistance, and heat resistance, and is also excellent in new required performance gasohol resistance and sour gasohol resistance, and also has good tensile strength. As it has strength, elongation and cold resistance, it can be used for various purposes such as automobile fuel system hoses, hoses that come into contact with fuel oil, hydraulic oil, lubricating oil, diaphragms, gaskets, O-rings, and oil seals. Various sealing materials, and various rolls or transmission belts, conveyor belts, timing belts, chain tensioners, oil dampers that require oil resistance and solvent resistance for iron making, spinning, printing, paper making, dyeing, etc. It can be used for

In particular, it can be suitably used as a rubber for a fuel system hose of an automobile by taking advantage of its excellent sour gasoline resistance and sour gasohol resistance.

e. Examples Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples as long as the gist thereof is not exceeded.

Examples 1 to 5 and Comparative Examples 1 to 2 The acrylic rubber (I) and acrylic rubber, fluororubber, conjugated diene-α, β unsaturated nitrile copolymer rubber and hydride thereof shown in Table 2 were prepared. For each sample of the blend composition of at least one rubber (II) selected from the other rubbers except the above and polyvinylidene fluoride (hereinafter referred to as "PVDF"), according to the formulation shown in Table-1, Banbury Blending was performed with a mixer. The obtained compound was press-cured according to the conditions shown in the lower part of Table 1.

The properties of the obtained crosslinked rubber were measured according to JIS K 6301. In addition, sour gasoline resistance and sour gasohol resistance were evaluated by the following methods.

Sour gasoline resistance 2.5 g of lauroyl peroxide dissolved in 97.5 g of Fuel C (mixed solvent of isooctane: toluene = 1: 1 (volume ratio)) was dipped into a test piece at 40 ° C for 72 hours. The test pieces were taken out in each cycle. 100 ° C
After vacuum drying for 15 hours, bend the test piece 180 degrees,
The state of crack generation was observed.

Except for using the mixed solvent of Fuel C and ethanol (volume ratio Fuel C: ethanol = 80:20) instead of sour gasohol resistance Fuel C,
The evaluation was performed in the same manner as the evaluation method for sour gasoline resistance.

The evaluation results are shown in Table-3.

From the results of Table-3, the vulcanized rubber composition of the present invention has excellent gasoline resistance, gasohol resistance, sour gasoline resistance, sour gasohol resistance, ozone resistance, heat resistance, and tensile strength. It can be seen that it is possible to provide a vulcanized rubber composition having excellent balance of elongation, elongation, gasoline resistance and cold resistance.

In Table-1, * 1) High Ablation Furnace Black * 2) First Excluding Furnace Black * 3) Semi-Rain Forcing Furnace Black * 4) Fatty Acid Metal Salt: Technical Processig Company * 5) Polyetherester Plasticizer: Adeka Argus Chemical Co., Ltd. * 6) Tributoxyethyl phosphate * 7) Dioctyl phthalate * 8) Triallyl isocyanurate * 9) Tetramethyl thiuram disulfide * 10) Dipentamethylene thiuram hexasulfide * 11) 1, 3-Diethylthiourea * 12) 2-Mercaptoimidazoline f. Effect of the Invention The vulcanized rubber composition of the present invention has gasoline resistance, sour gasoline resistance, gasohol resistance, sour gasohol resistance, ozone resistance, and heat resistance. Excellent and even Tsu tension strength, elongation,
A vulcanized rubber composition having an excellent balance of gasoline resistance and cold resistance.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Koji Nobu 2-11-24 Tsukiji, Chuo-ku, Tokyo Within Nippon Synthetic Rubber Co., Ltd. (56) Reference JP-A-52-40558 (JP, A) Kai 54-154446 (JP, A) JP 58-63740 (JP, A) JP 60-65048 (JP, A)

Claims (1)

[Claims] 1. An acrylic acid alkyl ester and / or an acrylic acid alkoxy-substituted alkyl ester compound (A) in an amount of 30 to 99.9% by weight, (B) a crosslinkable monomer in an amount of 0.1 to 10% by weight, and (C) the above (A), ( Acrylic rubber (I) having a polymerization composition of 0 to 70% by weight of other ethylenically unsaturated compound copolymerizable with B), and other rubbers (however, fluororubber, conjugated diene-α, β unsaturated nitrile) (II) and vinylidene fluoride resin (III) containing 90 mol% or more of vinylidene fluoride, and the weight ratio of (I) / (II) is 9
A vulcanized rubber composition, characterized in that the weight ratio of (I) + (II) / (III) is 9.9 / 0.1 to 70/30 and 95/5 to 40/60.